The RETINEX (Retina and Cerebral Cortex) algorithm is a commonly used image enhancement method which is developed based on scientific experiments and scientific analysis, and its theoretical basis is that a color of an object is decided by reflectivity of the object relative to light of a long wave (red), a medium wave (green), and a short wave (blue), instead of being decided by an absolute value of intensity of reflected light. The color of the object is not affected by non-uniformity of the light, and has consistency, that is, RETINEX is based on the color sensation consistency (color constancy). Compared with the linear and non-linear methods in the related art that only a certain type of features of an image can be enhanced, RETINEX can achieve balance among three aspects of dynamic range compression, edge enhancement, and color constancy, and therefore can adaptively enhance various types of images.
In practical applications, severe distortion may sometimes occur in the enhanced image obtained by the RETINEX algorithm in the related art.